1. Field of Invention
This invention relates to coin acceptors for use in coin operated vending and service devices, and in particular, a coin acceptor which will not allow the coin to leave contact with the customers hand and fully enter the acceptor until it has been validated as a good and proper coin.
Background 2. Description of Prior Art.
The objective of a coin operated vending machine is to receive coins, check them for validity as proper coins, and deliver the merchandise or service to the customer. If all goes well between the customer and the machine, the customer is usually happy, and the vending operator makes a fair return on his investment. Unfortunatly, when a vending machine fails to deliver the merchandise or service the customer has paid for, many customers become irate, inflicting damage to the machine. Vandalism by "ripped off" customers is a major financial loss to operators of unattended vending devices. The malfunctions of vending machines can, in most cases, be traced directly to coin accepting device. The coin acceptor accounts for up to 90% of all vending machine failures.
Several general types of coin acceptors are in use in vending machines today. The very complex acceptors commonly used in soft drink vending machines contain many moving parts, but work quite well in the clean dry environment where these machines are normally located. However, this type of acceptor would have a very short life expectancy if used in a self service car wash where the coin slot would receive water, soap and wax. A compromise of coin selectivity must be made in this harsh environment to eliminate the many small moving parts. The other extreme from the very complex soft drink acceptors would be the very simple type of acceptor used in many self service car washes which checks only the diameter of the coin by means of two opto beams. Between these two extremes are several different types of coin acceptors. Coin slide mechanisms such as described in U.S. Pat. No. 3,763,984 to Greenwald, have been used for many years primarily in laundromat washing machines, and various versions of this type coin acceptor are still supplied on many new machines. When this type of coin acceptor was introduced many years ago, the price of a wash was a single coin, and they worked quite well. As inflation occured, the price increased to require more coins, and various coin slides were developed to keep up with inflated prices. With wash prices up to eight coins today, it has become very difficult to design coin slides that operate properly. one type of slide acceptor stacks four stacks of coins flat in four round openings. Another type uses eight vertical slots in which the coins must be placed to operate it. In either of these types, one bad coin will prevent the slide from operating. The customer may not know which coin is the bad one, leading to confusion as to how to get the device to work. Bent coins can cause jamming in this type of acceptor, as the coins dissapear from view as the slide is pushed in, and can jam in such a way that the slide can not be pulled back out by the normal strength of the customer. Another type of acceptor accepts the coin into an opening in a rotary disc which allows a knob to be turned to release the vend. This type of acceptor is quite simple, but is very non selective as to the coins it will accept.
Coin acceptors utilizing low frequency magnetic detection methods are well known, as described in U.S. Pat. No. 4,359,148 to Davies, which compares the change in the frequency and amplitude as the coin passes an oscillating magnetic field between two coils. Another low frequency magnetic detecting type acceptor which is well known is described in U.S. Pat. No. 4,666,027 to Ostroski and Briski. This acceptor utilizes two sets of coils, one of which contains a sample coin between them, and another which compares the change in the frequency and amplitude as the coin drops between them. it also checks the speed at which the coin drops.
Advantages of the invention will become obvious as the readers ensue the following descriptions and drawings.